摘要：This paper analyzes some properties of the alternating separation (AS) and alternating projection (AP) algorithm. The analysis shows that AS converges to the optimal point steadily but slowly, while AP converges to the optimal point quickly but is prone to immersing into the local extreme of the maximum likelihood (ML) criterion. To avoid their disadvantages and make use of their advantages, ASAP, which is the combination of AS and AP, is proposed. Simulation results show that the ASAP algorithm has the ability of estimating the direction of arrival more accurately and converging to optimal point more quickly.